The present invention relates to an apparatus for the color matching of an automotive repair paint.
An automotive repair paint is used for a partial or overall recoating of the exterior of an automobile for repair or retouching. Usually in such automotive repair coating, it is necessary to reproduce a color substantially identical to the existing surface color of the automobile. Therefore, the color matching of a repair paint is a very delicate operation calling for many years of experience and much intuition.
Meanwhile, recent years have witnessed a great deal of diversification of automobiles not only in model but also in the color and kind of finish coating. Therefore, the color matching of repair paints is required to deal with an increasing diversity of coating compositions and hues.
When automotive repairing is performed as a business, it is essential to deal with each request for repair with high efficiency and provide an improved precision of repairing to thereby win the client""s, satisfaction. On the other hand, to realize a greater rationalization of color matching, it is getting more and more necessary to put ingenuity in the working procedure so as to minimize dependence on skill and reduce labor and time.
In order to improve the efficiency of a repair job by reconciling the above conflicting requirements, it is keenly demanded to introduce a practically useful color matching system involving a minimum of procedural steps requiring experience and perceptual acuity and enabling any one to attain a precision color matching with high efficiency in a short time.
Such a color matching system may not meet actual needs unless it is able to deal with both a solid paint and a metallic or pearlescent pigment containing paint(briefly a metallic or pearlescent paint). Moreover, such a system will not be practically useful if it is not easy to manipulate or work with.
The conventional computer color matching technology for determining an adequate formulation for a paint containing a metallic or pearlescent pigment comprises computing a colorant formulation conforming to a target color under a given coating parameter setting by convergence using the Kubelka-Munc optical density equation, determining a metallic or pearlescent pigment formulation necessary to reproduce a desired luster or hue by empirical judgement using available information, comparing a colored sample prepared with a paint of the formulation thus computed with the chromaticity and luster of a target color and adjusting the difference by repeated correction computation and visual evaluation aided by experience until an agreement in luster and hue has been finally obtained.
Japanese Kokai publication H2-184369 discloses an automatic weighing and color matching system comprising a computer unit and, connected thereto via a channel, a terminal unit and an automatic batching unit. However, this technology is such that color matching data are supplied from a master file on a computer and the system is not equipped with a mechanism for the color matching computation for paint formulation or a correction computation and is not sufficient in the precision and versatility of color matching.
Japanese Kokai publication H2-292699 discloses a weighing and color matching system comprising a computer unit and, as connected thereto by a telephone line, a MODEM and a calorimeter. Japanese Kokai publication H8-332438 discloses a weighing and color matching apparatus comprising a computer unit, a weighing station, a calorimetric station, a touch screen and a touch pen. With those technologies, however, it is a master computer connected to a public communication line that computes a paint formulation from measured data of a color sample and performs a correction computation and said computer unit processes the color matching formulation based on the results of computations received from said master computer via the public communication line. As such, this weighing and color matching apparatus does not have a system of its own for performing a color matching computation or a correction computation needed for paint formulation. Therefore, the processing speed is not as high as desired and the local data accumulated individually in the work place can hardly be reflected in the color matching computation, thus being not adequate enough in the quality of operation and workability. In addition, as far as chromatic coatings containing metallic or pearlescent pigments are concerned, a color matching technique taking the influence of metallic or pearlescent pigments on the output color into consideration has not been implemented as yet, with the result that in order to reproduce the desired hue and luster, it is necessary to back up the system with experience and intuition. For these reasons, the prior art cannot be sufficiently relied on for the purpose of improving the efficiency and rationality of a formulating operation.
Japanese Kokai publication H7-150081 discloses a method for reproducing a paint film color by computing the formulating amounts of paint component materials inclusive of colorants and metallic or pearlescent pigments, which comprises using known correlations of the amounts of components inclusive of colorants and metallic or pearlescent pigments with reflectance and carrying out a computational to obtain characteristic values corresponding to a new reflectance by interpolation using an inverse estimation technique. However, since this technique is a method of determining a relevant formulation by interpolation from known reflectance-characteristic value correlations, it is difficult to provide for a sufficient degree of freedom in formulation particularly in the case of paint film colors containing metallic or pearlescent pigments. Furthermore, what is disclosed is no more than a computer-aided color matching technology and no information is disclosed about a practically useful system which can be applied to actual automotive repairing for solving the above-mentioned problems.
Thus, in the prior art, particularly in connection with metallic or pearlescent paint colors, the computational means for finding a formulating ratio of metallic or pearlescent pigment to colorant pigment reproducing the desired hue and luster has not been implemented in a computer color matching system and the versatility in the formulation which can be dealt with is limited. Moreover, in order to obtain a formulation sufficiently matching the target color in both hue and luster, the computer color matching routine must be repeatedly executed or the trial coating be performed repeatedly on a trial-and-error basis relying on visual assessment and experience. This is because, in order to reproduce the desired hue and luster, the influence of metallic or pearlescent pigments on chromaticity must be taken into consideration, while the hue is influenced by the formulation of colorants and the coating thickness, among other factors, so that the computation must be carried out taking all such factors into account.
Particularly in the color matching of an automotive repair paint, unlike creative color designs and other jobs, a strict agreement with the currently prevailing coated color of an automobile to be repair-finished is required. In many cases, the prevailing coated color is not the same as the original color of a new automobile because of the fading and discoloration due to aging so that the color matching must be performed not based on the factory formulation data of the paint used on the automobile to be repair-finished but also taking the actually measured data on the automobile to be repaired into consideration.
Therefore, in the case of metallic or pearlescent colors which are increasingly used in those years, it is extremely difficult, even for a well-experienced specialist, to find a formulation giving a good match to a target color in both hue and luster. Thus, many trials are required until a necessary formulation has been attained so that the color matching takes much labor and time, thus increasing the cost of repairing. Moreover, even if many trials are carried out, there is no guarantee that the objective formulation can be certainly obtained. In addition, in order to construct a color matching system which should be practically useful, measures must be instituted to insure said accuracy of color matching and correct for the above-mentioned influence of fading or discoloration. Thus, the technical problems which must be solved for the establishment of a practical color matching system suited to automotive repair jobs remain yet to be solved.
In view of the above state of the art, the present invention has for its object to provide a color matching apparatus for automotive repair paints which enables even unexperienced personnel to perform color matching of a repair paint, whether containing a metallic or pearlescent pigment or not containing a metallic or pearlescent pigment, in a reduced number of steps and with high precision in a short time.
The present invention relates to a color matching apparatus for automotive repair paints which comprises a computer, a color display, a spectrophotometer capable of color measurement at a plurality of viewing angles, and an electronic balance wherein said color matching apparatus is provided, as installed on said computer, a color matching computation system capable of performing a color matching computation for an automotive repair paint, a color data file and a database reference system capable of referring to a remote database server for retrieval of at least paint component base data and automotive top coat formulation base data via a communication channel and, in response to a computation command is capable of carrying out a color matching computation for an automotive repair paint either containing or not containing a metallic or pearlescent pigment on the basis of calorimetric data obtained from said spectrophotometer and color data in said color data file and outputting the result of said computation to said color display and electronic balance, with said, apparatus, upon connection to the database server via said communication channel, being enabled to retrieve at least said paint component base data and automotive top coat formulation base data and use them in said color matching computation. The present invention is now described in detail.